onsemi 74LCXH32245GX

Overview

74LCXH32245 from Fairchild Semiconductor is a low-voltage 32-bit bidirectional transceiver with 5V-tolerant I/O, bushold inputs, and byte-level direction control. It operates at 2.3–3.6 V_CC, delivers 4.5 ns max propagation delay at 3.3 V, supports ±24 mA drive, and interfaces between 2.5/3.3 V buses and legacy 5 V systems in memory expansion and backplane interconnects.

For engineers reviewing the 74LCXH32245 datasheet, pinout, applications, or equivalent options, key selection criteria include 5V tolerance across all I/O, bushold-enabled input retention without external resistors, FBGA96A package compatibility, and byte-wise OE/T/R control for flexible bus segmentation.

Technical Context

The 74LCXH32245 implements four independent 8-bit bidirectional data paths, each with dedicated OE_n and T/R_n controls-enabling selective 8-bit, 16-bit, or full 32-bit operation. Its bushold circuitry actively holds floating inputs at their last valid logic state using internal feedback, eliminating external biasing.

It features power-off high-impedance I/O, live insertion support, and patented EMI/noise reduction circuitry. Absolute maximum ratings allow 7.0 V on I/O pins (with V_CC = 0 V), and latch-up immunity exceeds 500 mA per JEDEC JESD78.

Key Specifications

Pinout & Package

Packaged in 96-ball Fine-Pitch Ball Grid Array (FBGA), JEDEC MO-205 compliant, 5.5 mm × 5.5 mm body, 0.8 mm ball pitch, BGA96A package.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar bidirectional transceiver applications.

Compared with 74LCXH32245, the 74ALVC16245 lacks bushold and requires external biasing, while the SN74LVC3245A consolidates control logic but sacrifices byte-granular bus management-making 74LCXH32245 optimal for segmented, mixed-voltage, high-reliability interconnects.

Availability

74LCXH32245 is available at Aetrix Electronics and suitable for memory expansion interfaces, PCI bus bridges, hot-swappable carrier cards, and low-power FPGA I/O buffering requiring stable component supply and long-term obsolescence management.

Supply support for 74LCXH32245 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Fairchild Semiconductor was a U.S.-based analog and power IC manufacturer acquired by ON Semiconductor in 2016; known for high-performance logic, MOSFETs, and power management solutions.

The 74LCXH32245 belongs to Fairchild's LCX family of low-voltage, high-speed CMOS logic devices designed specifically for mixed-signal, mixed-voltage system interconnects in computing, telecom, and industrial equipment.

FAQ

What voltage levels does the 74LCXH32245 support on its I/O pins?

The 74LCXH32245 supports input and output voltages from 0 V to 5.5 V regardless of V_CC level, enabling direct interfacing with 5 V logic while powered from 2.3–3.6 V supplies. This 5V tolerance is specified across the full operating temperature range (−40°C to +85°C) and applies to all A0–A31 and B0–B31 pins. The 74LCXH32245 achieves this via internal clamping structures that protect the core logic without compromising speed or leakage.

Does the 74LCXH32245 require external pull-up or pull-down resistors on unused inputs?

No-the 74LCXH32245 integrates bushold circuitry on all inputs, which actively retains the last valid logic state without external components. Bushold provides ±75 µA minimum hold current at 2.0 V input, ensuring stable HIGH or LOW states even when inputs float. This feature directly eliminates the need for 10 kΩ pull resistors typically required on unused pins of standard transceivers like the 74LVC3245.

How is bidirectional data flow controlled on the 74LCXH32245?

Data direction is controlled per byte using four independent T/R inputs (T/R1–T/R4), where LOW enables B→A transfer and HIGH enables A→B transfer. Each byte also has its own OE input (OE1–OE4) to place both A and B ports in high-impedance state. This byte-level granularity allows concurrent 8-bit, 16-bit, and full 32-bit operations on shared buses-unlike single-control transceivers such as the SN74LVC3245A.

What package type is used for the 74LCXH32245 and what are its mechanical dimensions?

The 74LCXH32245 is packaged in a 96-ball Fine-Pitch Ball Grid Array (FBGA), designated BGA96A, compliant with JEDEC MO-205. It measures 5.5 mm × 5.5 mm with 0.8 mm ball pitch and 0.3 mm ball diameter. The package uses solder balls arranged in a 10×10 array with corner balls omitted, supporting automated placement and reflow in high-density PCB assemblies.

Can the 74LCXH32245 be used in hot-swap applications?

Yes-the 74LCXH32245 supports live insertion/withdrawal due to power-off high-impedance I/O, robust ESD protection (>2000 V HBM), and latch-up immunity exceeding 500 mA. When V_CC is removed, all I/O pins enter high-Z state automatically, preventing bus contention. This behavior is validated per Fairchild Application Note AN-5007 and makes the 74LCXH32245 suitable for modular backplanes and carrier cards requiring field-replaceable modules.